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#1 Nick Anderson

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Posted 06 November 2013 - 05:53 AM

I had a quick notation question on marking orientations for some sketches I did over the weekend: for a solar eclipse, is it better to use celestial cardinal points versus ones relative to the Sun's poles? Better yet, would it be confusing to always use celestial cardinal points for general Sun sketches? :question: I'm curious to hear what you all think.

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#2 Asbytec

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Posted 06 November 2013 - 06:07 AM

Is there a standard set somewhere? For example, ALPO likes planetary sketches submitted with north down. If you look at their images, planetary north is always at the bottom of the sketch. Maybe some solar observing sights have set a standard and you can follow that.

"If possible, We want you to turn the planetary South Pole up." (North down, same - same...LOL)

http://alpo-j.asahik...c.jp/indexE.htm

#3 David Gray

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Posted 06 November 2013 - 01:28 PM

South-up used to be pretty universal till NASA came along and befuddled it.

From a more selfish point I would be happy to use north-up as I have used an Amici prism (erect/unreversed) for some years now and occasionally forget to invert my sketches for reporting.

ALPO-Japan: there is the occasional 'rogue' that gets away with north-up - especially Jupiter. Also at least one imager that seems to find it necessary to show both orientations.....! :confused:

Cheers,
David.

#4 Asbytec

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Posted 06 November 2013 - 07:41 PM

So, David, what convention do you use? Many times I simply orient it as seen at the eyepiece. But, south-up is becoming my norm (after one rogue posting on ALPO and being corrected for it.) Preceding is as seen, either left or right.

#5 Ernest_SPB

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Posted 07 November 2013 - 12:51 AM

Some standard orientation is essential when you'd like to compare two sketches of the same object, or a sketch to photo. I think north up, west left is most natural and usually rotate my sketches in to the position after scanning, before publishing. But while drawing I use convenient orientation (to have the same in eyepiece and on paper).

#6 Nick Anderson

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Posted 07 November 2013 - 02:40 AM

So it sounds like celestial cardinal points are the way to go (even for the Sun), then beyond that it can be debated whether to use "[celestial] south is up", "[celestial] north is up", or "as seen in eyepiece".

How about the Moon: celestial or selenographic? This is where the notation might get confusing/ambiguous, as east and west are flipped between the two.

-Nick Anderson

#7 David Gray

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Posted 07 November 2013 - 02:54 AM

So, David, what convention do you use? Many times I simply orient it as seen at the eyepiece. But, south-up is becoming my norm (after one rogue posting on ALPO and being corrected for it.) Preceding is as seen, either left or right.


Well I maintain (for reporting) the traditional south-up/west left as required by the BAA planetary sections. That is, in the main, the s. pole at the top and west (preceding side) left as seen at the meridian when facing south. (Mercury, Venus,Mars, Jupiter); Saturn I use a little artistic licence giving 5º or more tilt/slant - but still south-up. All of this used to be taken for granted years back in conformity with the usual inverted view in the scope with very minimal misunderstanding: then NASA (and IAU??). Add to that diagonals - mirror/prisms (erecting, reversing etc); in my case Amici (erect/non-reversing)!

With Uranus & Neptune I especially strive to remove ambiguity by indicating field directions more specifically but still maintaining the traditional (BAA, ALPO et al) south at the top and west (prec.) left. In their case disregarding poles and as would be seen on the meridian - leaving the telescopic view out of it you might say!

I suppose it is Anne-fairy-Anne which orientation we use as long as we indicate it clearly on our presentations/reports and such. Maybe for correctness we should be so doing this indicating with all of our submissions regardless how obvious, to most of us, it may be: e.g. Jupiter/Saturn.

Cheers,
David.

#8 Asbytec

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Posted 07 November 2013 - 06:27 AM

If west is left as a standard, I have to reverse my sketches. Using a diagonal with a CAT, west is to the right when south is up. :)

Yea, I agree, just indicate it clearly unless there is a standard for submission.

#9 David Gray

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Posted 07 November 2013 - 08:05 AM

OK Norme: I was a little worried I had muddied the waters even more so just in case did a graphic using WinJupos.


But here it is anyhow: Jupiter is the ideal example but it's applicability to the Sun (also on WinJupos) etc is hopefully evident.

Diagonals can really confuse things; also Newtonians - depending on eyepiece positions. I find using the binoviewer with the Amici eliminates a lot of the 'skewed' angles I suspect by it compelling me to stand (in my case) more level. I know with single/mono-Amici views a lot of odd slants were apparent at times. Never gave it much study but easy to check out clouds obliging!

Of course, as we know, the diurnal drift across the field gives a guide to the cardinal points. This is my means of estimating double star p.a. in any case. Or with an equatorial mount moving the scope in R.A.

Cheers,
David.

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#10 Asbytec

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Posted 07 November 2013 - 08:33 AM

David, no, you didn't muddy the water. If you did, I missed it. :)

Yea, crossing the meridian from east to west does strange things. Still, it's easy enough to rotate south up. It's a little harder to reverse east and west in the sketch. It could be done, though, with image processing.

#11 Knuklhdastrnmr

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Posted 07 November 2013 - 09:48 AM

I just move the scope up and right and note where the stars enter the field. That's N and W. I note that on my sketch but put the stars and objects in as they appear in my eyepiece.

#12 Ed D

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Posted 07 November 2013 - 10:11 AM

I make my sketches oriented just as they appear in the eyepiece, no matter if I'm using a refractor or reflector. If I were submitting the sketches to an organization that has a format preference I would adjust them in the computer to comply with that format.

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#13 David Gray

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Posted 07 November 2013 - 11:39 AM

Thanks Norme: I guess my long-winded 'clarifications' here might give some the impression I have some difficulty with directions. In fact it's not an issue with me at the scope: especially with the Amici which shows things the same way up as me! Then as my scope has no drive I always know - stars whatever- from field-drift the parallel with the celestial equator. I don't have to even think about it: my concern being that I convey to whoever clearly/unambiguously in my reporting.

Reversal of drawings: very simple with Corel Draw and other such graphics software - even the MS Word/Excel drawing tools have this capability (Draw: Flip Horizontal); tho' possibly more labour-intensive depending on version. Corel is a breeze - one mouse click after Object Selection: two max - and of course so much more than Word etc!

Cheers,
David (Seated upright, facing s'east.) :grin:

#14 Asbytec

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Posted 07 November 2013 - 08:11 PM

David, you mean you've not gotten lost? ;)

Yea, if we digitize the image, it seems no problem to reverse it. Most software can do that. (I use paint.net.)

So, south-up, west-left? I'd think so in keeping with BAA and ALPO standards and extending them to other objects unless there is a standard in place for them.

Still, something unnatural bugs me about reversing an image from how we observed it. Maybe it's an acquired taste. I did get queried about my own orientation sketching some doubles (with south up, that was the view.) It's a good question, maybe it needs an answer (if we're gonna be anal sometimes.) Or maybe not as long as direction is clear. Still, looking at images and sketches on the net, it's sometimes difficult to orient yourself or your own sketch. Orientation varies from image to image.

So, whose gonna go enforce this in the imaging forum? "Hey, put that image upside down! I can't understand it." :)

Seated upright facing south east, lighting is from the south south west. (I think) :grin:

#15 stanislas-jean

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Posted 08 November 2013 - 01:46 AM

Orientation is a part of the situation, be aware anyway of the devices in use before the eyepiece.
The rotation direction of the planet is also a question, as normal and retrograde.
Anyway when the features appears quitely, the situation is quickly acquired.
Stanislas-Jean

#16 David Gray

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Posted 08 November 2013 - 05:30 AM

Still, something unnatural bugs me about reversing an image from how we observed it. Maybe it's an acquired taste.


OK Norme: If I understand you are perhaps somewhat in the camp of those that want get everything they see exactly as presented in the eye-circle/field including the circle with some.

If I were to do that I would have to include such as (with planets especially) the diffraction effects of the apodizer! Not to mention a huge in-scale field circle. As I have said other threads on here I'm a draughtsman first trying to keep a tight rein on my inner artist - I have to decide what is peripheral and what is relevant to what I want to portray with the recipient in mind (BAA etc) I might depart from that for such as forums and loosen up artistic-wise. The totally true depiction of the scene presented in the scope might be called the Anthropic one - as far as I know the objects we study are oblivious to us! Getting OP here - themes for other threads somebody.....?? Me - no: too much pressing at present!

I think whatever floats our boats :D and that can only enrich the Forum if done thoughtfully/carefully/respectfully.

Cheers,
David.

#17 Asbytec

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Posted 08 November 2013 - 08:58 AM

David, at risk of venturing off topic, not really that level of detail noting every aspect of the FOV...just the target and maybe some field stars for reference when needed. I guess what I meant was, rather off the cuff, reversing the image would "feel" unnatural. Rotating south up is fine...emotionally. :)

#18 David Gray

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Posted 08 November 2013 - 09:23 AM

Yes Norme, as I indicated, did not think you would be that extreme!

Anyhow as far as the topic goes I do not think I have any more to offer; hoping my WinJupos attachment covers the bases.

Will have to disappear for a while anyway - those pressing matters: Richard McKim (BAA Mars) is pushing me for my 1997/98 Saturn observations - long story. Many drawings to 'scan' in: south-up (slyly back on-topic!) with an artistic-licence of a 15º slant of the rings/globe; well Paul Doherty used to do it, so good enough for me.

Hope that storm is bypassing you - I need to brush up on my geography: thought you lived in the USA. :o

Take care,
David.

#19 Asbytec

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Posted 08 November 2013 - 10:21 AM

Thanks David for the thoughts on the storm, it passed far enough south of us. Reports coming in from the Visayas (Central PI) they took the brunt.

So, yea, in the end maybe south up and preceding left is fine. The only remark I had left was the unnatural feel for festoons point the other way than observed and playing havoc on PA for double stars as observed (using diurnal drift, as well.) Stan mentioned retrograde motion, but I think that means west to the left in most cases, too.

Good luck with your work, need to check out BAA. Cheers.






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